SAVANNAH, Ga. - A warning that terrorists are plotting an attack in the United States this summer will have little effect on the security strategy at next month's G-8 summit, officials said Wednesday.

"I don't see these new threats being reported changing anything we have in place," said Barry Bennett, spokesman for the federal Summit Planning Organization. "The security is already a 10, it doesn't go to 11. We're maxed."

Authorities plan to have 20,000 federal, state and local law enforcement officers secure the area and help guard President Bush and the leaders of U.S. allies during the economic summit June 8-10.

FBI Director Robert Mueller said "extraordinary precautions" already were being taken to protect such major events, including the dedication of a World War II monument in Washington this weekend and the two political conventions - the Democratic convention in Boston in July and the Republican convention in New York in August.

The G-8 summit will be held on Sea Island, about 80 miles from Savannah. The island will be closed off with a security net of Secret Service agents, National Guard troops and Coast Guard gunboats.

Airspace along Georgia's 100 miles of coastline, extending into South Carolina and northern Florida, will be virtually shut down to private planes. Waterways will be off-limits to private boats for up to three nautical miles off Sea Island.

Attorney General John Ashcroft issued the terror warning, citing "credible intelligence from multiple sources." The intelligence does not contain specifics such as timing, method or place of an attack.

Jim Evans of San Marcos, Calif., said he still plans to attend Saturday's ceremony for the World War II monument in Washington.

"It concerns me, but you can't live your life in fear. You have to go about your business," said Evans, 80, who served in the Marine Corps during World War II. "It's just like telling me it's going to rain. What are you going to do about it?"

About 117,000 people have reserved tickets for the event, and U.S. Park Police plan to use metal detectors and check visitors' bags.

Chris Eich, who works a block from where the Republican National Convention will be held in New York, said he will avoid crowds and traffic, but he's confident the area will be "very well protected."

Mike Erlandson, a Democratic convention delegate from Minnesota, said he's concerned about terrorism in general.

"But at this point I probably, as will most people, fear the long lines at the metal detectors more than anything that might happen."